Spilopteron nigromaculatum, Pham & Broad & Matsumoto & Achterberg, 2019

Pham, Nhi Thi, Broad, Gavin R., Matsumoto, Rikio & Achterberg, Cornelis Van, 2019, First records of the genus Spilopteron Townes (Hymenoptera: Ichneumonidae: Acaenitinae) from Vietnam, with descriptions of five new species, Zootaxa 4590 (1), pp. 153-165 : 159-160

Spilopteron nigromaculatum sp. nov.

( Fig. 5 )

Material examined. Holotype: ♂ ( IEBR), Tuyen Quang Province, Na Hang, 1–10.vi.2017, Malaise trap, L.D. Khuat leg.; paratype: 1♂ ( IEBR), Hoa Binh Province, Mai Chau, Tan Son , 20–25.iv.2010, 850– 900 m a.s.l., Malaise trap, L.D. Khuat leg.

Description of holotype male. Head. Antenna with 41 flagellomeres, first flagellomere 1.35× length of second; frons concave and polished medially, punctate laterally, carina between antennal sockets extending to face dorsally; face 0.65× as high as wide, coarsely striate-punctate medially, finer punctures laterally; clypeus about 0.5× as high as wide, subpolished, with sparse, punctures, median tubercle smaller than lateral ones, apico-lateral corner with striations; malar space slightly longer than basal width of mandible; exposed part of labrum about 0.5× as long as basal width; inner margins of eyes divergent ventrally; diameter of lateral ocellus 0.6× ocellar-ocular distance; vertex with sparse punctures; occipital carina evenly curved, ventrally meeting hypostomal carina about 0.9× basal mandible width from base of mandible.

Mesosoma. Pronotum with striations across median groove and dense, small punctures at posterior corner; mesoscutum slightly longer than width at anterior level of tegulae, with dense punctures, pubescent; scutellum densely punctate, pubescent, lateral carina extending to basal 0.75; metanotum polished, impunctate; mesopleuron smooth, impunctate medially, ventrally with dense punctures, pubescent, epicnemial carina complete; metapleuron subpolished, with dense, small punctures, pubescent, submetapleural carina complete; propodeum with area basalis smooth, area externa with dense, small punctures, pubescent, area superomedia and area petiolaris polished, impunctate, except for anterior wrinkles in area petiolaris, area dentipara not defined and with many wrinkles, pubescent; fore basitarsus 2.5× second tarsomere; mid basitarsus 2.5× second tarsomere; hind leg with femur 4.8× as long as wide, 0.7× length of tibia, basitarsus 2.1× second tarsomere. Fore wing length 10.2 mm, vein M&RS distad of 1 cu-a, vein 2 rs-m slightly distad of 2 m-cu, hind wing with first abscissa of vein CU 1.4× length of vein cu-a.

Metasoma. Tergites with small punctures, pubescent; first tergite 3.3× as long as posterior width, subpolished, with sparse punctures, lateral longitudinal carina shortly present anteriorly; second tergite 0.4× as long as first tergite, wider than long, slightly longer than third, with dense, small punctures, pubescent; sclerotized part of first sternite reaching 0.6× length of tergite, to level of spiracle; aedeagus as shown in figure 5f, with penis valve about 1.5× as long as basal apodeme, basal apodeme with round tip.

Colour. Black with yellow as follow: scape, pedicel, flagellomeres 12 to 23, face, inner orbit, clypeus, mandible teeth (except distal ends), labrum, gena ventrally, scutellum, metanotum, tegula, subalar prominence, propodeum posteriorly, very narrow bands on tergites 1–6 posteriorly, posterior half of tergite 7 and entire tergite 8, entire fore and mid legs, hind trochanter, trochantellus, proximal 0.75 of hind tibia and entire hind tarsus. Wings with apical margin infuscate, fore wing with distinct black mark below pterostigma.

Female. Unknown.

Comparison. This species is most similar to Spilopteron tosaense (Uchida, 1934) in general appearance. It differs from the latter by the presence of the white median band of the antennal flagellum, the presence of a depression between eye and antennal socket, and the shape of the aedeagus, which has penis valve about 1.5× as long as basal apodeme, with a round basal apodeme tip (vs. penis valve about 2.0× as long as basal apodeme, with a pointed basal apodeme tip in S. tosaense (see Ito & Maeto, 2017).

Etymology. This species is named after the black spot below the pterostigma of the fore wing.

Distribution. Currently known from Tuyen Quang and Hoa Binh provinces, North Vietnam.

Figures

FIGURE 5. Spilopteron nigromaculatum sp. nov., holotype male: a. habitus, lateral view; b. face; c. lateral view of head and mesosoma; d. propodeum; e. wings; f. lateral view of aedeagus (of paratype).